Here is the full list of all 12 Rock Band Classic Rock Track Pack achievements worth 250 gamerscore.
5-Starred "Holiday in Cambodia" by Dead Kennedys using Bass or Vocals on any difficulty.
5-Starred "Peace of Mind" by Boston using Vocals or Guitar on any difficulty.
5-Starred "Take the Money and Run" by Steve Miller Band using Guitar or Drums on any difficulty.
5-Starred "The Joker" by Steve Miller Band using Guitar or Vocals on any difficulty.
5-Starred "All Right Now" by Free using Guitar or Vocals on any difficulty.
5-Star "Closer to the Heart" by Rush using either Vocals or Drums on any difficulty.
5-Star "Can't Stand Losing You" by the Police with a full band.
Gold Star "Rock and Roll Band" by Boston with a full band.
Score 100% notes hit as bassist, up-strums only, on Expert.
Score 100% notes hit as a guitarist on Expert.
Score a 100% rating as a vocalist on Expert.
Score 100% notes hit as a drummer on Expert.